CN113456311A

CN113456311A - Split bionic femoral stem prosthesis

Info

Publication number: CN113456311A
Application number: CN202110880834.6A
Authority: CN
Inventors: 郭卫; 郭煜
Original assignee: Peking University Peoples Hospital
Current assignee: Peking University; Peking University Peoples Hospital
Priority date: 2021-08-02
Filing date: 2021-08-02
Publication date: 2021-10-01

Abstract

The invention relates to a split bionic femoral stem prosthesis, which comprises a proximal femoral connecting part and a distal stem body part; wherein the proximal femur connecting part is detachably connected to the upper end of the distal stem part, the upper end of the proximal femur connecting part is used for being connected with the proximal femur intramedullary canal, and the lower end of the distal stem part is used for being inserted into the distal femur intramedullary canal, thereby replacing the defective femur section. The proximal femur connecting part and the distal stem body of the invention adopt a split type design of threaded connection, the structure not only has the anti-rotation effect of a taper connection mode, but also is firmer and more durable than the taper connection, and the embarrassment that the distal stem body is remained in the distal medullary cavity of the femur and can not be taken out because of the looseness of the taper connection can not occur in the process of prosthesis renovation.

Description

Split bionic femoral stem prosthesis

Technical Field

The invention relates to an artificial prosthesis, in particular to a split bionic femoral stem prosthesis, and belongs to the technical field of medical instruments.

Background

With the increasing incidence of osteoarthritis and other diseases affecting the bones and joints, the need for Total Hip Arthroplasty (THA) has also increased. By 2030, over 600000 people are expected to receive THA annually in China, highlighting the importance of extending prosthesis life and reducing the risk of prosthesis revision.

At present, the service life of the femoral stem is averagely 11.42 years. With the increase of the population life and the trend of the diseases such as femoral head necrosis, the prosthesis service life of about 10 years can not meet the requirements of patients. After the prosthesis fails, a revision surgery is required, and the replacement of the new prosthesis continues to be in service. Some young patients often undergo revision surgery more than once, bear enormous physical, psychological and economic stress, and add additional burden to society. Therefore, how to increase the service life of the prosthesis becomes an urgent economic and social problem to be solved by clinicians and researchers.

The most prominent cause of femoral stem failure is mechanical failure. After the femoral stem is implanted into a femoral medullary cavity, the femoral stem can bear the influence of acting forces in multiple directions such as axial torsion, longitudinal extrusion, horizontal bending and the like and resultant force thereof in the normal motion process of a human body. Bone cement fixation (cement type) is often the most rare at the beginning of femoral stem implantation, either by proximal press-fit (biologic type) or initial implantation. However, the early immediate stability of either type of fixation is achieved by the interaction between the host bone and the prosthesis or cement. However, the femoral stems used in the clinical practice at present have the following problems:

firstly, femoral stems designed by most manufacturers are flat, and the shape of a femoral medullary cavity after the medullary cavity is filed and polished is similar to an ellipse and round; therefore, the contact with the host bone B after the femoral stem a is implanted is a point contact (as shown in fig. 1), and as a result, all the stress is concentrated on the contact point of the stem and the bone before the integration of the medullary cavity and the femoral stem, which may cause serious complications such as fracture, abrasion, bone loss, osteolysis, etc. around the prosthesis over time, resulting in failure of the prosthesis;

secondly, the biological type femoral stem near end is prepared into a so-called biological coating through sand blasting, titanium particle spraying or hydroxyapatite sintering to be beneficial to osseointegration, but the binding force of the coatings is not ideal, and the coating is easy to fall off when implanted, which may promote the periprosthetic osteolysis in the subsequent use process; in addition, these coatings often only have irregular protrusions or ravines on the femoral stem surface, and there is no space for deep growth through bone tissue, so it is considered that this osseointegration cannot reach a very ideal state;

the selectable types of the femoral stems clinically used at present are limited, and the use requirements of all patients cannot be met; the femoral medullary cavity of patients has various forms, the distal medullary cavity of the femur of some patients is thinner, the medullary cavity of the proximal tuberosity part is normal or thicker, the patients only can move about the narrower distal medullary cavity of the femur and select a small-size femoral stem prosthesis, and the problems brought by this way are that the proximal press-fit effect of the femur is poor, and the initial stability of the prosthesis is poor; in addition, the contact between the proximal bone and the bone is insufficient, and the long-term osseointegration effect is not ideal.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a split bionic femoral stem prosthesis which is firm and durable, has a wide stress distribution range, good long-term stability and long service life.

In order to achieve the purpose, the invention adopts the following technical scheme: a split bionic femoral stem prosthesis comprises a proximal femoral connecting part and a distal stem body part; wherein the proximal femur connecting part is detachably connected to the upper end of the distal stem part, the upper end of the proximal femur connecting part is used for being connected with the proximal femur intramedullary canal, and the lower end of the distal stem part is used for being inserted into the distal femur intramedullary canal, thereby replacing the defective femur section.

The split bionic femoral stem prosthesis is characterized in that the proximal femoral connecting part comprises a neck root part (11) and a neck top part, a female head with internal threads is processed at the lower end of the neck root part, the neck top part is integrally formed at the upper end of the neck root part, and the neck top part is used for being inserted into a proximal femoral medullary cavity.

Preferably, the distal stem body part comprises a stem rod and a male head with external threads, which is integrally formed at the upper end of the stem rod, and the male head threads of the distal stem body part are screwed into the female head of the neck root part and are tightly connected into a whole.

The split bionic femoral stem prosthesis is characterized in that the neck top of the proximal femoral connecting part and the stem of the distal stem body part are respectively in an oval shape matched with the proximal femoral medullary cavity and the distal femoral medullary cavity.

The split bionic femoral stem prosthesis is preferably characterized in that the proximal femoral connecting part is formed by personalized customization through a 3D printing technology, and the bending degree and the thickness of the proximal femoral connecting part are designed and manufactured according to the shape of a proximal femoral medullary cavity of a patient.

Preferably, the outer surface of the neck root part of the proximal femur connecting part is prepared into a porous metal bone trabecula structure with the pore size of 400-600 mu m and complete communication by a partial 3D printing technology, the porosity is more than 80%, and the pore layer thickness is 2 mm.

The split bionic femoral stem prosthesis is preferably prepared by machining the distal stem body.

Due to the adoption of the technical scheme, the invention has the following advantages:

1. the proximal femur connecting part and the distal stem body are in threaded connection and are in split type design, so that the structure not only has the anti-rotation effect of a taper connection mode, but also is firmer and more durable than the taper connection, and the embarrassment that the distal stem body is remained in the distal medullary cavity of the femur and cannot be taken out due to the looseness of the taper connection in the process of prosthesis renovation can be avoided;

2. the neck top of the proximal femur connecting part and the handle rod of the distal handle body are respectively in an oval shape matched with the proximal femur medullary cavity and the distal femur medullary cavity, so that a completely bionic effect is achieved, the prosthesis can be in close contact with each wall of the femur medullary cavity after being implanted, the point contact of the existing flat femur handle is converted into the more extensive surface contact, the stress distribution on the wall of the femur medullary cavity is greatly reduced, and serious complications such as fracture, abrasion, bone loss, osteolysis and the like around the prosthesis are effectively avoided;

3. the proximal femur connecting part is prepared by using a 3D printing technology, and the outer surface of the neck root part of the proximal femur connecting part is provided with the porous metal bone trabecula structure by using a part of the 3D printing technology, so that a growing space is provided for a new bone tissue, the new bone tissue can creep and grow into a pore structure and form firm osseointegration, the long-term stability and the service life of the prosthesis are greatly improved, and the problem of falling caused by insufficient binding force of a coating is completely solved;

4. the distal handle body is prepared by adopting a machining mode, so that the preparation time of the prosthesis can be greatly shortened, the hospitalization waiting time is shortened, and the benefits of patients are brought;

5. the split type design of the invention can respectively select the proximal femur connecting part and the distal stem body part with different types to be assembled according to the diameters of the proximal femur intramedullary canal and the distal femur intramedullary canal, thereby perfectly solving the problem that the existing integrated femur stem has single type and cannot simultaneously match the intramedullary canal and the tuberosity part;

6. on one hand, the bionic femoral stem prosthesis is based on clinical requirements, on the other hand, the bionic femoral stem prosthesis is developed with longer service life and better mechanical property by following social guidance and facing the problems of the younger hip joint diseases, the longer service life of the elderly and the like, and a brand-new thought is provided for the development of the hip joint prosthesis and the treatment of the hip joint diseases.

Drawings

FIG. 1 is a schematic view of a conventional femoral stem in point contact with a host bone after implantation;

fig. 2 is a schematic structural diagram of a split bionic femoral stem prosthesis according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of the split bionic femoral stem prosthesis provided in the embodiment of the present invention at another view angle;

FIG. 4 is a schematic view of a proximal femoral connection provided in accordance with an embodiment of the present invention;

FIG. 5 is a schematic view of a proximal femoral connection according to another embodiment of the present invention;

FIG. 6 is a schematic view of a distal handle portion according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the system or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The split bionic femoral stem prosthesis comprises a near-end femoral connecting part and a far-end stem body part, wherein the near-end femoral connecting part and the far-end stem body part are in split type design of threaded connection, the upper end of the near-end femoral connecting part is used for being connected with a near-end femoral medullary cavity, and the lower end of the far-end stem body part is used for being inserted into the far-end femoral medullary cavity, so that a defective femoral segment is replaced. The structure not only has the anti-rotation effect of the taper joint mode, but also is more firm and durable than the taper joint, and the embarrassment that the distal handle body is remained in the distal medullary cavity of the femur and can not be taken out because of the looseness of the taper joint can not occur in the process of repairing the prosthesis.

The split bionic femoral stem prosthesis provided by the embodiment of the invention is described in detail below with reference to the accompanying drawings.

As shown in fig. 2 and 3, the split-type bionic femoral stem prosthesis provided in this embodiment includes a proximal femoral connecting portion 10 and a distal stem body portion 20, wherein the proximal femoral connecting portion 10 is detachably connected to an upper end of the distal stem body portion 20, the upper end of the proximal femoral connecting portion 10 is used for connecting with a proximal femoral medullary cavity, and the lower end of the distal stem body portion 20 is used for inserting into a distal femoral medullary cavity, thereby replacing a defective femoral segment.

In the above embodiment, preferably, as shown in fig. 4 and 5, the proximal femoral connecting part 10 includes a neck base 11 and a neck top 12, a female head 13 with an internal thread is formed at a lower end of the neck base 11, the neck top 12 is integrally formed at an upper end of the neck base 11, and the neck top 12 is adapted to be inserted into a proximal femoral medullary cavity.

In the above embodiment, preferably, as shown in fig. 2 and 6, the distal stem body 20 comprises a stem 21 and a male head 22 with external threads integrally formed at the upper end of the stem 21, and the male head 22 of the distal stem body 20 is screwed into the female head 13 of the neck root 11 to be tightly connected together, so that the structure not only has the anti-rotation effect of the taper joint manner, but also is more durable than the taper joint, and the embarrassment that the distal stem body 20 remains in the distal femoral medullary cavity and cannot be taken out due to the loosening of the taper joint does not occur during the revision of the prosthesis.

In the above embodiment, preferably, the neck top portion 12 of the proximal femur connecting portion 10 and the stem 21 of the distal stem body portion 20 are respectively in an elliptical shape matching with the proximal femur medullary cavity and the distal femur medullary cavity, so as to achieve a completely bionic effect, the prosthesis can be in close contact with each wall of the femur medullary cavity after being implanted, the existing point contact of the flat femur stem is changed into a more extensive planar contact, the stress distribution on the femoral medullary cavity wall is greatly reduced, and serious complications such as fracture, abrasion, bone loss, osteolysis and the like around the prosthesis are effectively avoided.

In the above embodiment, preferably, as shown in fig. 4 and 5, the proximal femoral connecting part 10 is customized by using 3D printing technology, and the bending degree and thickness thereof are designed and manufactured according to the shape of the proximal femoral medullary cavity of the patient and are completely matched; further, the outer surface of the neck root part 11 of the proximal femur connecting part 10 is prepared into a porous metal bone trabecula structure with the pore size of 400-600 μm and complete communication through a partial 3D printing technology, the porosity is more than 80%, and the pore layer thickness is 2mm, so that a growing space is provided for the new bone tissue, the new bone tissue can creep into the pore structure and form firm osseointegration, the long-term stability and the service life of the prosthesis are greatly increased, and the problem of falling caused by insufficient binding force of the coating is completely solved.

In the above embodiment, the distal stem 20 is preferably machined, because the proximal femur connecting part 10 is mainly used for fixing the primary hip replacement femoral stem prosthesis, and the machining of the distal stem 20 can greatly shorten the preparation time of the prosthesis, shorten the waiting time in hospital, and benefit a great number of patients.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The split bionic femoral stem prosthesis is characterized by comprising a proximal femoral connecting part (10) and a distal stem body (20);

wherein the proximal femur connector (10) is detachably connected to the upper end of the distal stem portion (20), the upper end of the proximal femur connector (10) is adapted to be connected to the proximal femoral medullary cavity, and the lower end of the distal stem portion (20) is adapted to be inserted into the distal femoral medullary cavity, thereby replacing the defective femoral segment.

2. The split biomimetic femoral stem prosthesis according to claim 1, wherein the proximal femoral connecting part (10) includes a neck base part (11) and a neck top part (12), a female head (13) with internal threads is processed at a lower end of the neck base part (11), the neck top part (12) is integrally formed at an upper end of the neck base part (11), and the neck top part (12) is used for being inserted into a proximal femoral medullary cavity.

3. The split bionic femoral stem prosthesis according to claim 2, characterized in that the distal stem part (20) comprises a stem (21) and an externally threaded male head (22) integrally formed at the upper end of the stem (21), and the male head (22) of the distal stem part (20) is screwed into the female head (13) of the neck root (11) and tightly connected together.

4. The split biomimetic femoral stem prosthesis according to claim 3, wherein the neck top portion (12) of the proximal femoral connecting portion (10) and the stem (21) of the distal stem portion (20) are elliptical to match the proximal femoral medullary cavity and the distal femoral medullary cavity, respectively.

5. The split bionic femoral stem prosthesis according to claim 1, wherein the proximal femoral connecting part (10) is customized by 3D printing technology, and the bending degree and thickness of the proximal femoral connecting part are designed and manufactured according to the shape of the proximal femoral medullary cavity of a patient.

6. The split bionic femoral stem prosthesis according to claim 5, wherein the outer surface of the neck root part (11) of the proximal femoral connecting part (10) is prepared into a porous metal bone trabecular structure with a pore size of 400-600 μm and complete communication by a partial 3D printing technology, the porosity is above 80%, and the pore layer thickness is 2 mm.

7. The split bionic femoral stem prosthesis according to any one of claims 1 to 6, characterized in that the distal stem part (20) is prepared by machining.